基于线粒体Cyt b 和核基因ZFY 探讨羊族物种之间的系统发生关系

为了阐明羊族物种之间的系统发生关系并解决岩羊属中矮岩羊物种的有效性问题,本文测定了来自金沙江河谷地区栖息于林线以上岩羊和林线以下矮岩羊共226 份粪便DNA 样品的线粒体Cyt b 基因全序列(1 140 bp)和核基因ZFY 部分序列(612 bp),结合从GenBank 中检索到的羊族物种同源DNA 序列进行比较,利用最大简约法和最大似然法构建分子系统发育树,根据获得的拓扑结构初步探讨它们的系统进化关系。结果表明,绵羊属的绵羊与山羊属、塔尔羊属、岩羊属各物种亲缘关系最远,喜马拉雅塔尔羊和岩羊属、山羊属的亲缘关系最近。在进化树的岩羊属这一分支中,金沙江河谷地带岩羊和矮岩羊与内蒙古、青海、四川其它地理种群的岩羊聚为一支,同时分布在这一区域的部分岩羊和矮岩羊在Cyt b 基因和ZFY 基因单倍型上存在共享现象。历史上的气候事件可能造成金沙江河谷地带岩羊和矮岩羊种群之间相互迁移,偏雄性扩散促进了各地理种群之间的基因交流。因此不支持矮岩羊为独立的物种,建议将金沙江河谷地带的岩羊和矮岩羊都划分到岩羊四川亚种(Pseudois nayaur szechuanensis)。由于它们的形态和生态上存在一定的分化,建议将林线以下矮岩羊作为一个独立的管理单元进行保护与管理。

Exploring the phylogenetic relationships among species of tribe caprini based on mitochondrial Cyt b and nuclear gene ZFY

To explore the phylogenetic relationships among tribe caprini and the species validity of Pseudois schaeferi in Pseudois,the total sequence of mitochondrial Cyt b (1140 bp)and partial sequence of the nuclear gene ZFY (612 bp) were detected in 226 fecal DNA samples of Pseudois nayaur and Pseudois schaeferi living above and below the forest line, respectively,in the valley area of the Jinsha River. These sequences were compared to the homologous DNA sequences of the tribe caprini retrieved from GenBank,then we reconstructed phylogenetic tree using maximum parsimony,maximum likelihood methods,primarily to investigate the phylogenetic relationship among these species based on obtained topological structure. The results showed that the kinship was the farthest between Ovis and other genera including Capra,Pseudois and Hemitragus. Hemitragus jelahicus was the nearest relative between Pseudois and Capra. Pseudois nayaur and the Pseudois schaeferi living in the valley area of Jinsha River are classified as the same branches as the Pseudois nayaur living in Inner Mongolia,Qinghai and Sichuan. They share the same haplotypes of Cyt b and ZFY with some Pseudois nayaur andPseudois schaeferi living in the valley area of Jinsha River. The climatic events in history might lead to the intermigration of Pseudois nayaur and Pseudois schaeferi living in the valley area of Jinsha River,and male-biased dispersal promoted the gene exchanges among different geographic populations. Thus,Pseudois schaeferi should not be classified as an independent species,we advise that Pseudois nayaur and Pseudois schaeferi living in the valley area of Jinsha River be classified as Pseudois nayaur szechuanensis. The dwarf Pseudois nayaur should be managed independently due to the distinctive evolutionary characteristics in morphology and ecology.